1. Field of the Invention
The present invention relates to a rear wheel steering mechanism for a four-wheel-steerable (4WS) vehicle, the rear wheel steering mechanism having an acuator for turning rear wheels.
2. Description of the Relevant Art
Four-wheel-steering systems for use in automobiles are roughly classified into those in which front and rear wheels are mechanically coupled to each other and those in which rear wheels are turned by an actuator without mechanical connection to front wheels.
In the latter system using an actuator, when reactive forces from the road are applied to the rear wheels, the rear wheels may be turned by such reactive forces since the driver is unable to feel those reactive foeces because the rear wheels are not mechanically coupled to the front wheels and hence to the steering wheel.
Japanses Laid-Open Patent Publication No. 61-196870 published Sept. 1, 1986 and Japanese Laid-Open Utility Model Publication No. 61-31972 published Feb. 26, 1986 disclose steering mechanisms each having an actuator or electric motor for turning vehicle wheels, the mechanism including a locking device or arrangement for preventing the wheels from being turned under external forces.